Coded signal relay



Sept. 16, 1958 Filed July l0, 1957 v A. c. REYNOLDS, JR

CODED SIGNAL RELAY 2 Sheets-Sheet 2 psv/cs asv/cs -ra se 70 5F camfaasov4/revu@ INVENTOR.

nited States Patent O CODED SIGNAL RELAY Andrew Craig Reynolds, Jr.,Waterbury, Conn., assignor to General Time Corporation, New York, N. Y.,a corporation of Delaware Application July 10, 1957, Serial No. 670,955

6 Claims. (Cl. 307--140) This invention relates to remotely controlledrelays and more particularly to a switch actuating relay responsive to acoded signal.

Relays of this type are primarily intended for use in a system whichincludes armaster signal transmitter and a plurality of relays connectedto a common power supply line. particular coded signal pattern and thustheitransmitter can selectively actuate any desired relay by sending theproper code on the power line. Systems of this nature have foundparticular utility when installed on a regular 60 cycle, A.C. power linewith the relays being responsive to high frequency signals superimposedyon the line by the transmitter. In this way, appliances receiving powerfrom the line can be remotely controlled from a central station.

One of the major difficulties in setting up a system of the typereferred to above is the problem of providing a simple and completelyreliable coded signal relay that is immune to spurious transient signalswhich are found to occur at random in an A.C..power system. Suchtransient signals are commonly generated by various forms of heavy dutyelectrical equipment which may be installed in the system and haveabrupt wave fronts comprising many frequency components. Often thespurious signal will include a component having the frequency at whichthe relays are set to respond and thus a false code is transmitted onthe power line which has proven troublesome in such remote controlsystems.

It is therefore an object to provide a novel coded signal responsiverelay which is immune to spurious transient signals and which willoperate only upon receiving the proper code signals of sustainedduration. It is a collateral object to provide a relay of this characterwhich is simple in design and completely reliable in operation.

In more detail it is an object to provide a relay of the typecharacterized above which is constructed of conventional cam controlledswitches and driven by ordinary timing motors so as to be economical tomanufacture. It is a related object to provide such a relay having fewparts, and those operating under very light mechanical forces, so thatthe relay remains reliable and accurate over a long and trouble-freeservice life.

It is another object to provide a relayof the'type referred to abovethat is simple and convenient to set for,

response to a particular desired coded signal.

In one of its aspects it is an object of the invention to provide anovel relay of the type discussed above which can supply a controllingcurrent impulse to either of two devices in response to a further codesignal transmitted remotely from the central control station.

Other objects and advantages of the invention will become apparent uponreading the attached detailed description and upon reference to thedrawings in which:

Figure l shows a schematic wiring diagram of a coded signal relayconstructed in accordance with the present invention.

Each of the relays is adjusted to respond to Ya seal-in the motor 20through a complete cycle of 'oper-` 2,852,705 Patented Sept. 1 6, 1 958|ee ICC Fig. 4 shows a fragmentary perspective View of a timel delaydevice utilized in the relays shown in Figs. 1 and 3.

Fig. 5 is a fragmentary elevation view of the mounting of an adjustablecam on its camshaft.

While the invention will be described in connection with certainpreferred embodiments, it will be understood that I do not intend tolimit the invention to those embodiments. On the contrary, I intend tocover all alterations, modifications and equivalents as may be includedin the spirit and scope of the invention as de-v fined by the appendedclaims.

Turning lirst to Fig. 1, there is schematically shown a remotelycontrolled, switch actuating, relay 10, constructed in accordance withthe present invention, con-- nected between a device 11 to be controlledby therelay and the power lines 12, 13 of an A.C. power sys'- tem. TheA.C. power system may include a plurality of similarly connected relays,identical to the relay 10,l and a high frequency signal transmitter ofany convert-- tional type which is effective to superimpose a high fre-'quency signal on the normal 60 cycle A.C. power sys-1 tem (Seel-Iig.la).

In order to detect high frequency signals in the power' system and causethe relay 10 to properly respond there-- to, a high frequency signalreceiver 15 is connect-ed across the lines 12, 13. The receiver 15 maybe of anyr` convenient type such as are well known in systems off thisnature.

In accordance with the present invention, the relay 10 includes a timingmotor which is energized and sealed-- in for one operating cycle whenthe receiver 15 responds. to an initiating code signal impulse ofpredetermined. duration, and a second timing motor which is activatedunder the concurrent control of the rst motor and a'. second, properlytimed code signal impulse of predetermined duration for operation of thecontrolled device 11. In the illustrated embodiment, the first motor 20is in the form of a self-starting, synchronous motor, of the typecommonly employed in electric clocks and other timing devices, which isenergized for a single cycle of operation whenever an initiating signalis received by the high frequency signal 15. In order to energize themotor' 20 in response to a high frequency signal, the receiver 15actuates a control relay 21 which closes a set of contacts 22 andcompletes a circuit, through the normally closed contacts 23, connectingthe motor 20 to the A.C. power system lines 12, 13. The motor 20 isprovided with a gear box 25 which rotates a camshaft 26 through a timedelay device 30, to which later detailed reference will be made. In thepreferred embodiment, the motor 20 and the gear box 25 are effective 4torotate the camshaft 26 at an angular speed of 11/5 R. P. M.

Since the initiating signal which causes the energization of the controlrelay 21 and the closing of the contacts 22 lasts only a short timeinterval, a circuit is provided to trated, the cam 31 is provided with asingle drop-oit` portion 33 allowing the contacts 32 to lopen, and,there--` fore, once the contacts 32 are closed by the cam 31,

3 they will remain closed for a full revolution of the camshaft 26,which is one cycle of operation. Since the shaft 26 rotates at 11/5 R.P. M., the cycle of operation for the relay 10 requires a time intervalof 50 seconds.

Once the camshaft 26 begins rotation and the motor 20 is sealed-in bythe circuit through the `contacts 32, the contacts 23 are opened todisassociate the circuit controlled by the relay 2l from the motorcontrol circuit. This is accomplished in the present embodiment byfixing a cam 36 to the camshaft 26 which is effective to open thecontacts 23 when the shaft 26 begins rotating and hold them open untilthe operating cycle of the motor 20 is completed. This preventscompletion of a circuit through the contacts 32-to the remainingcircuitry shown in the lower portion of Fig. l and described below.

, lt will be appreciated that when a number of relays similar to therelay llt) are connected to a common A.C. power system, each willrespond in the manner describe-d above when the master transmitter unitimposes an initiated signal onto the common A.-C. power system. ln orderto select the relay lt) for operation, to the exclusion of other,ditferently adjusted relays, a second high frequency signal must betransmitted on the lines 12, i3 following the first signal by aparticular, selected time interval. In the present embodiment, when asecond properly timed signal of predetermined duration is received bythe high frequency signal receiver i5, a second timing motor 40 isactivated, which in the present instance is a self-starting, synchronousmotor similar to the motor 20.

In order to activate the motor 40 only in response to a second codedsignal impulse occurring at a selected time during the operating cycleof the motor 2d, a positionable timing cam 4i is secured to the camshaft2o. The cam al carries a single lobe 42 which is eifectiye to operatethe contacts 43 only at a selected time during the single revolution ofthe camshaft 26 representing one cycle of relay operation. rfhe secondtiming motor 4t) is energized when the receiver l activates the relay2l, in response to a second coded signal impulse, during the sameinterval in which the lobe 42 is effective to operate thc contacts 43.The concurrent operation of the relay 21 and the contacts 413 closesboth the contacts 22 and the contacts 43, to complete a circuit from theA.C. :power lines f2, 13 to the second motor di?. The motor providedwith a gear box 4S which rotates a camshaft 46 through a time delaydevice 47 identical to the time delay device 3h, and which will be laterdescribed in detail. In the preferred embodiment, the motor 4i? and thegear box i5 are effective to rotate the camshaft 46 at the same angularspeed at which thc camshaft is driven, that is, l/s R. P. M.

ln order to seal-in the motor 40 for operation through a. completecycle, a cam (i3 is fixed to the camshaft sie and is effective to closethe contacts 9. Thus, when the motor 40 remains energized for a timeinterval sufficient to rotate the camshaft 46 through the time delaydevice 47, the cam 4S will close the contacts 49. This will complete acircuit bypassing the contacts 43, and will thus maintain the motor it?energized until the cam 48 completes a single revolution and again opensthe contacts 49.

Once the motor d@ is energized and sealed-in, it is effective totransmit the desired current impulse for the control of the device ll.To accomplish this, a control impulse cam 51 is adjustably fixed to thecamshaft 46 and is provided with a lobe 52 which is effective to closethe contacts 53 for a selected interval during the rotational cycle ofthe second motor 40. Closing the contacts 53 completes a direct circuitfrom the lines l2, lls to the device il. The duration of the currentimpulse applied' to the device l1 will depend upon the dimension of thecam lobe 52, and in practice it has been found desirable to standardizethis current impulse interval to either three, tive or eight seconds byproviding standard cams with suitably shaped cam lobes.

is-y

it will be apparent that the device 1l may consist of a visual oraudible signal, such as an electric light or bell respectively, or maycomprise a latching relay which will be tripped by the current impulsesupplied by the relay 10 so as to switch on or off an electricalappliance of any desired type.

it will be understood that the angular position of the cam 41 -on thecamshaft 26 will determine the particular coded signal to which therelay 10 will respond. ln order to set the relay for response to anygiven coded signal, therefore, it is sufficient merely to change theangular relationship of the cam 41 with respect to the camshaft 26. Tofacilitate this adjustment, the cam 41 is loosely mounted adjacent ashoulder 26a formed on the camshaft and a nut 55 is threaded on to thecamshaft (see Fig. 5). The nut may be drawn up to tighten the camagainst the shoulder 26a, and thus rigidly tix the adjustable cam in anydesired angular position.

Once the second motor 49 has been energized and sealedin, it will beunderstood that the current impulse transmitted to the device 11 dependsupon the angular position of the cam S1 yon the camshaft 46. In order tohave this current impulse transmitted at a single definiteY shaft 45 ina' manner identical to the mounting on thel cam il described above. Inthis way, the time interval required for the cam 4l to close theycontacts 43, in respouseV to a particular code, plus the ltime intervalrequired for the cam 51 to close the contacts 53, for transmitting thecurrent impulse to the device fi, can always be adjusted to be aconstant desired value.

ln the illustrated embodiment for example, the cam 41 has beenpositioned ou the camshaft 26 so that the contacts 43 are closed thirtyseconds following the initial energization of the motor 2t). The relay1t) will then respond to a code comprising an initiating signal followedin thirty seconds by a second signal. It is desirable to transmit thecurrent impulse to the device 11 at fifty seconds past the beginning ofthe coded signal. Since the second signal begins the rotation of themotor L50, the cam 51 must be annularly adjusted on the camshaft 46 toclose the `contacts 53 twenty seconds following the energization andsealing in of the second motor 40. It will be understood then, that themotor 4t) will be energized thirty seconds following the initial signalimpulse of the codey and, twenty seconds following this, the contacts 52will be closed. Thus, the current impulse to the device .l1 will betransmitted fifty seconds following thestart of the coded signal. Whenthe relay l0 is adjusted to respond to a somewhat dilferent code, theangular position of the cam 41 must be changed on the camshaft'd, and,to keep the operating time ol the device 11 constant, the cam 51 is alsoannularly adjusted on the camshaft 46 so that the operating timerequired to clo-se contacts 43 and the contacts 53 remains a total offifty seconds.

For the purpose of transmitting a current impulse to the device 11 onlywhen a high frequency signal of predetermined duration is received, andthus prevent operation of the relay 10 by spurious, transient signals,the time delay devices 30 and 47 are provided. As mentioned above,spurious, high-frequency signals are often induced in an A.C. powersystem by various electrical devices, these signals being a form ofstatic and possessing frequency components within a range which willcause a response from the high-frequency signal receiver 1S. Suchspurious signals, however, are of short duration and therefore atransient signal received by the high-frequency signal receiver willcause only a momentary activation of the control relay 21, which onlybriefly closes the contacts 22. By providing the motors 20 and 4t) withtime delay devices, the brief closings of the contacts 22 caused byspurious, transient signals will be of insufficient duration toinitially seal-in the motor 20 or to later seal-in the motor 40, andthus the relay-14)v will be immune to false operating cycles caused byltransient signals. l

j The time delay devices 30 yand 47 are identical and therefore it willbe convenient to describe only the device 30 in detail, and for thispurpose reference will be made to Fig. 4. In the present embodiment, thetime delay device 30 comprises a spring-biased, lost motion, drivingconnection 'between the output shaft of the motor 20 and the camshaft26, which is arranged so that when the motor starts rotating, it mustfirst overcome the spring force and take up the lost motion before thecamshaft 26r is rotated. To provide the lost motion connectionthe gearbox 25 associated with the motor 20 is connected to drive a disk 60mounted concentrically with, but independently of, the camshaft 26. Thedisk 60 rotates the camshaft 26 by means of a pin 61 extending axiallyof the camshaft through a hole 62 of somewhat greater diameter formed inthe cam 31. It can be seen that when the pin is disposed at one edge ofthe hole 62, themotor 20 must rotate the disk 60 through a distanceapproximately equal to the diameter of the hole 62 so that the pin 61may engage the opposite side of the hole and impart a rotational forceto the cam 31.

To insure that the disks 60 and the motor 20 are properly backed off sothat the pin 61 is adjacent the proper edge of the hole 62, a torsionspring 63 is fixed to the camshaft 26 and is tensioned to exert aresilienty -force against the pin 61 in a direction opposite to thatimparted by the motor 20. It can thus be seen that momentaryenergization of the motor 20, caused by the brief closing of thecontacts 22 as a result of spurious, transient signals being picked upby the high frequency signal receiver 15, will only cause the disk 60 tobegin revolving and start to carry the pin 61 across the hole 62. Uponthe almost immediate deenergization of the motor20, the torsion spring63 will return the pin 61, disk 60 and the gear trainl included withinthe gear box 25, kback to their'original lstarting position. It will beapparent then, that the operation of the relay can be initiated only byenergizing the motor 20 for a sustained, predetermined period, whichwill be the case when a true signal impulse of several seconds durationis transmitted on the A.-C. power system. In a practical case, signalimpulses of four seconds duration for the initial code signal and twoseconds duration for the second signal have been found to be effective.

Tol hold the camshaft 26 and the cam 31 in their starting positionsagainst the reactive force exerted by the torsion spring 63, theinherent detenting effect provided by the switch actuator for thecontacts 32 is utilized. As can be seen in Fig. 4, the contacts 32 areprovided with la resilient switch actuator 65 having a detent portion 66which drops into the notch-like dropoifA portion 33 of the cam 31. Itwill be understood that the engagement of the switch actuator 65 withinthe drop-off portion 33 will hold the cam 31 andthe camshaft 26 in theirrespective starting positions with a detent action. When the motor 20remains energized for a time sufficient to bring the pin 61 intoengagement with the opposite side of the hole 62, the lcam 31 will berotated so `as to bring the detent portion 66 of the switch actuator 65out of the drop-off portion 33 so that the contacts 32 are closed andthe operating cycle of the motor 20 initiated.

In order to minimize the resilient force required to be exerted by thetorsion spring 63, while insuring that the force is sufficient to backoff the disk 60 and the gear train in the gear box 25, the motor 20preferably includes an automatically operating clutch of the type Whichis commonly employed for such purposes. In clutch motors of this type,the motor armature is automatically engaged with the power outputdriving train upon energization of the motor winding, and is disengagedupon the deenergization of the motor winding An example of a motor ofthis type having such an automatically operating clutch construction canbe seen by reference to the United States Patent to Schellens, No.2,234,040, issued November 9, 1943. It will be sufficient for presentpurposes to observe that the armaturegin the motor 20 is connected tothe driving train in the gear box 25 only when the motor is energized.When the motor is only briey energized through the action of a spurioussignal causing the contacts 22 to flutter momentarily, the gear train inthe gear box 25 Vand the disk 60 are briefly advanced by the motorarmature and then completely disconnected from the armature. Thus, thetorsion spring 63 need rotate only the disk 60 and the gears within thegear box 25 back to their initial starting positions, and is notrequired to rotate the entire armature of the motor 20.

The relay 10 can be modified for selectively controlling either one oftwo devices in response to a third signal impulse in the coded signal.This modification of the invention is shown in Fig. 3, in which a relay10a is v schematically illustrated with the parts similar to thosedescribed above having been given the same numerical designation withthe distinguishing suflix a added. The relay 10a is Aconnected betweenthe power lines 12a, 13a and the two devices to be controlled 71 and 72.A highfrequency signal receiver 15a is connected across the lines 12a,13a so as to activate a relay 21a in response to a high-frequency signalimpulse on the A;C. control system. As in the operation of the relay 10discussed above, the initial signal impulse of the coded signal willcause the receiver 15a to actuate the relay 21a and close the contacts22a to thus complete a circuit through the normally closed contacts 23aand energize the motor 20a. If the motor remains energized during thedelay period imposed by the time delay device 30a, the cam 31a willclose the contacts 32a and seal-in the motor 20a for a complete cycle ofoperation.'

During the operating cycle of the motor 20a, the cam 41a will close thecontacts 43a to energize the second motor 40a if a second, properlytimed, signal is received. If the motor 40a remains energized throughthe time interval imposed by the time delay device 47a, it will sealitself in by means of the cam 48a closing the contacts' In accordancewith a further aspect of the invention, the relay 10a is provided with adouble output circuit, one circuit for each of the controlled devices 71, 72, and the control relay 21a is effective to determine which of theoutput circuits will be conditioned to transmit the desired currentimpulse for operating one of the devices. In the present embodiment, thecontrol relay 21a is activated and sealed-in as a result of a thirdsignal impulse in the coded signal. This is accomplished by providing acam 75, fixed to the camshaft 46a, which is effective to close thecontacts 76 just before the end of the operating cycle of the relay 10a.If a third signal impulse is received by the receiver 15a during thetime interval when the contacts 76 are closed, the activation of therelay 21a will close the contacts 22a and seal-in the control relay bymeans of the circuit through the contacts k22a and 76. When the controlrelay 21a is sealed-inthe contacts 22a remain closed and thus an outputcircuit to the device 71 is conditioned. lf Vhowever, the coded signaldoes not include a third signal impulse the control relay 21a will notbe activated and a set of normally closed contacts 77 under the controlof the control relay will remain closed. When the contacts 77 areclosed, the second of the two output circuits, which leads to the device72, will be conditioned.

In'order to complete Whichever of the two control circuits has beenconditioned, two cams 81 and 82. are adjustably mounted on the camshaft46a and are effective to close the contacts 83, 84, respectively, in thesame mannerras the cam 51 closes the contacts 53 in the,

7 first described modification shown in Fig. 1. It will be apparent thatif the normally closed contacts 77 remain closed because no third signalimpulse was included in the coded signal, the closing of the contacts 84will complete a circuit to the device 72 and thus transmit the desiredcurrent impulse to that device. If however, the coded signal includes aproperly timed third signal impulse, the control relay 21a will beactivated and sealedin so that closing of the contacts 83 by the cam S1will complete a circuit through the contacts 22a and S3 to transmit thedesired current impulse to the device 71.

Rsum f operation In order to briey review the operation of the relay 10,reference will be made to the chart shown in Fig. 2, where it can beseen that when the relay is at rest the contacts 23 are closed and therelay ready fer operation.

When the first coded signal impulse is detected by the receiver 15, thecontrol relay 21 is actuated and the contacts 22 are closed to completea circuit energizing the motor 20. The motor 20, upon being continuouslyenergized for the delay period imposed by the device 3i), is effectiveto rotate the cam 31 and close the contacts 32 and thus seal-in themotor 2i) for continuous operation throughout a complete cycle, which inthis case lasts 50 seconds.

At a certain selected interval during the operating cycle of the motor20, the cam 41 will be effective to close the contacts 43, and when asecond signal impulse of the coded signal is received concurrently withthe closing of the contacts 43, the motor 40 will be energized. 'As wasthe case with the motor 20, if the motor 40 remains energized through adelay period, it will be effective to rotate the cam 49a and close thecontacts 49, sealing in the motor 46 for a complete cycle of operation.p

During the operating cycle of the motor 40, it will be effective torotate the cam S1 so as to close the contacts 53 and complete a directcircuit from thepower lines 12, 13 to the device 11 which is to becontrolled. In the preferred embodiment the cam 51, as was stated above,has been angularly adjusted on the camshaft 46 so that it will close thecontacts 53 at exactly fifty seconds following the start of the codedsignal impulse.

It will be apparent that the relay 10 is completely immune to theeffects of spurious, transient signals and will not transmit a currentimpulse to the device 11 in response to a false code made up of acombination of spurious signals. This is due to the operation of thetime delay devices 30 and 47. Both the initiating signal required toenergize and seal-in the motor 2t), and the second timed signal requiredto energize and seal-in the motor 40, must be of a steady determinedduration so that the respective motors can take up the slack in theassociated lost motion devices and close the contacts sealing in theiroperation for a complete cycle. In practice, it has been found that thetime delay devices 3i), 47 should require a sustained signal duration ofapproximately two seconds. Since spurious, transient signals are of onlyfleeting duration, even though they may occur in a series, theirresulting intermittent actuation of the relay 21 will not cause themotors 20 and 40 to seal themselves in, and thus the relay 10 remainsimmune to such false signal patterns.

It will be appreciated that the relay 10 can be economically constructedsince it utilizes easily formed camcontrolled switches and conventionaltiming -motors of standard design.

I claim as my invention:

1. A coded signal relay for transmitting a current impulse to acontrolled device comprising, in combination, a signal responsivereceiver, a constant speed timing motor, means including said receiverfor energizing said motor through a complete cycle of operation inresponse to a signal of predetermined duration, means concurrentlycontrolled by said receiver and said motor to activate a timing deviceupon receipt of a second signal at a predetermined selected time duringsaid cycle, output terminals connected to said controlled device andmeans controlled by said timing device, when activated, to transmit thedesired current impulse to said output terminals for operation of saidcontrolled device.

2. A coded signal relay for transmitting a current impulse to a controldevice comprising, in combination, a signal responsive receiverincluding a relay actuated when a signal is received, a constant speedtiming motor, means including said relay for energizing said motor,means operated by said motor to maintain the energization of the motorthrough a complete cycle of operation following an initial motorenergization period of predetermined duration, means concurrentlycontrolled by said relay and said motor to activate a timing device uponreceipt of a second signal at a predetermined selected time during saidcycle, output terminals connected to said controlled device and meanscontrolled by said timing device, when activated, to transmit thedesired current impulse to said output terminals for operation of saidcontrolled device.

3. A coded signal relay for transmitting a current impulse to acontrolled device comprising, in combination, a signal receiverincluding a relay which is actuated when a signal is received, aconstant speed timing motor, means for energizing said motor when saidrelay is actuated, means for maintaining energization of said motorthrough a predetermined cycle, a second constant speed timing motor,means controlled by said rst motor for energizing said second motor whena second relay actuating signal is received at a selected predeterminedtime following the start of said cycle, means for maintaining nenergization of said second motor through a predetermined cycle, outputterminals connected to said device, and means operated by said secondmotor for transmitting a current impulse to said output terminals duringits operating cycle for operation of said controlled device.

4. A coded signal relay for transmitting a current impulse to acontrolled device comprising, in combination, a signal receiverincluding a relay which is actuated when a signal is received, aconstant speed timing motor, means for energizing said motor when saidrelay is actuated,

`means for maintaining energization of said motor through apredetermined cycle following an initial motor energization period ofpredetermined duration, a second constant speed timing motor, meansincluding a cam controlled switch operated by said lirst motor forenergizingV said `second motor when a second relay actuating signal isreceived at a selected predetermined time following the start of saidcycle, means for maintaining energization of s'aid second motor througha predetermined cycle following an initial second motor energizationperiod of predetermined duration, output terminals connected to saidcontrolled device, and means operated by said second motor fortransmitting a current impulse to said output terminals during itsoperating cycle for op- -eration of said device.

5. A coded signal relay for selectively transmitting a current impulseto one of two controlled devices comprising, in combination, a signalreceiver including a relay which is' actuated when a signal is received,a constant speed timing motor, means for energizing said mo- Y tor whensaid relay is actuated, means for maintaining energization of said motorthrough a predetermined cycle, a second constant speed timing motor,means including a cam controlled switch operated by said first motor forenergizing said second motor when a second relay actuating signal is'received at a selected time following the start of said cycle, means formaintaining energization of `said second motor through a predeterminedcycle, an output circuit having two alternate sets of output terminals,means operated by said second motor for transmitting a current impulseto said output circuit during its operating cycle, and means, includingsaid relay activated by said receiver when a signal is received, fordirecting said current impulse to one set of output terminals when therelay is activated as a result of a third signal for operation of one ofsaid controlled devices and to the other set of output terminals whenthe relay is not so energized for operation of the other of saidcontrolled devices;

6. A coded signal relay for selectively transmitting a current impulseto one of two controlled devices comprising, in combination, a signalreceiver including a relay which is actuated when a signal is received,`a constant speed timing motor, means for energizing said motor whensaid relay is actuated, means for maintaining energization of said motorthrough a predetermined cycle following an initial motor energizationperiod of predetermined duration, a second constant speed timing motor,means including a cam controlled switch operated by said first motor forenergizing said second motor when a second relay actuating signal isreceived at a selected predetermined time following the start of saidcycle, means for maintaining energization of said second motor through apredetermined cycle following an initial second motor energizationperiod of predetermined duration, an output circuit having two alternatesets of output terminals, means operated by said second motor fortransmitting a current impulse to said output circuit during itsoperating cycle, and means, including said relay activated by saidreceiver when a signal is received, for directing said current impulseto one set of output terminals when the relay is activated as a resultof a third signal for operation of one of said control devices and tothe other set of output terminals when the second relay is not soenergized for operation of the other of said control devices.

No references cited.

